Series of questions related to water change stations

[WarDog]

I would aim for 25-50% every 2 weeks. Others might suggest a smaller amount every week, but I find that too much work. Personally I do 25% every other Saturday, mixing and aerating the night before. This works well for what I've got.

As far as the Ontario winters and mixing outside, I wouldn't have a clue, never been there. Here in BC, zero is considered low in winter.